Rails - NoMethodError even though method is defined - ruby-on-rails

Question

So my goal with this method is to have it link to customers/1/showcar similar to how it will link to customers/1/edit, which is how I'm attempting to model my code.
My controller is
class CustomersController < ApplicationController
before_action :set_customer, only: [:show, :edit, :update, :destroy, :showcar]
# GET /customers
# GET /customers.json
def index
#customers = Customer.all
end
# GET /customers/1
# GET /customers/1.json
def show
end
# GET /customers/1/showcar
def showcar
end
# GET /customers/new
def new
#customer = Customer.new
end
# GET /customers/1/edit
def edit
end
# POST /customers
# POST /customers.json
def create
#customer = Customer.new(customer_params)
respond_to do |format|
if #customer.save
format.html { redirect_to #customer, notice: 'Customer was successfully created.' }
format.json { render :show, status: :created, location: #customer }
else
format.html { render :new }
format.json { render json: #customer.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /customers/1
# PATCH/PUT /customers/1.json
def update
respond_to do |format|
if #customer.update(customer_params)
format.html { redirect_to #customer, notice: 'Customer was successfully updated.' }
format.json { render :show, status: :ok, location: #customer }
else
format.html { render :edit }
format.json { render json: #customer.errors, status: :unprocessable_entity }
end
end
end
# DELETE /customers/1
# DELETE /customers/1.json
def destroy
#customer.destroy
respond_to do |format|
format.html { redirect_to customers_url, notice: 'Customer was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_customer
#customer = Customer.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def customer_params
params.require(:customer).permit(:cust_id, :cust_fname, :cust_lname, :cust_phone, :cust_addr, :cust_date)
end
end
and my html.erb file where I'm attempting to call the method is
<style>
th, td{
padding-left: 20px;
}
</style>
<p id="notice"><%= notice %></p>
<h1>Customers</h1>
<table>
<thead>
<tr>
<th>Cust ID</th>
<th>Cust fname</th>
<th>Cust lname</th>
<th>Cust phone</th>
<th>Cust addr</th>
<th>Cust date</th>
<th colspan="3"></th>
</tr>
</thead>
<tbody>
<% #customers.each do |customer| %>
<% belongstocust = Car.where(cust_id: customer.cust_id) %>
<tr>
<td><%= customer.cust_id %></td>
<td><%= customer.cust_fname %></td>
<td><%= customer.cust_lname %></td>
<td><%= customer.cust_phone %></td>
<td><%= customer.cust_addr %></td>
<td><%= customer.cust_date %></td>
<td><%= link_to 'Show', customer %></td>
<td><%= link_to 'Edit', edit_customer_path(customer) %></td>
<td><%= link_to 'Destroy', customer, method: :delete, data: { confirm: 'Are you sure?' } %></td>
#placeholder, not permanent code
<% i = '' %>
<% belongstocust.each do |car| %>
<% i = car.car_model %>
<td><%= link_to 'Show ' + i, car_path(car) %></td>
<% end %>
<td><%= link_to 'Show Car', showcar_customer_path(customer) %> </td>
</tr>
<% end %>
</tbody>
</table>
<br>
<%= link_to 'New Customer', new_customer_path %>
<br>
<%= link_to 'Home', home_index_path %>
The issue is, whenever I have the code <td><%= link_to 'Show Car', showcar_customer_path(customer) %> </td>, I get the noMethodError even though the method is defined inside the controller, and it looks the exact same as def show and def edit. I've tried making a controller called customer, and adding the showcar method to that controller, and it worked, but it wouldn't pass over the customer. I also tried adding showcar to customer.rb, but it also gave me a noMethodError. I'm a complete noob when it comes to ruby, and was just told to make a project using the framework, so I've been having to learn along the way. This could be a really simple issue that I don't know how to solve due to my ignorance, so if that's the case I'm sorry.

Answer 1

I get the noMethodError even though the method is defined inside the controller
No. You have showcar defined, not showcar_customer_path. You are missing a route, the thing that defines xxx_path methods.
In your config/routes.rb you probably have
resources :customers
To register this new action, you can do
resources :customers do
member do
get :showcar
end
end
Now showcar_customer_path should be available to use in the views.